JP2016029674A - Solid-state image pickup device - Google Patents

Abstract

A sensitivity difference between phase difference pixels in a central portion and a peripheral portion of a light receiving region is reduced without degrading the image quality of a captured image. A solid-state imaging device includes a plurality of normal pixels, a right phase difference pixel, and a left phase difference pixel in a light receiving region where an image of a subject is formed. A normal pixel receives incident light isotropically. Each of the right phase difference pixel and the left phase difference pixel has openings that are eccentrically arranged on the right side and the left side, respectively, and selectively receive light reaching the right side and the left side of incident light. The right phase difference pixel 42a in the left peripheral portion 11bL of the light receiving region has an area of the opening 56R larger than that of the central portion 11a and the right peripheral portion 11bR. Conversely, the left phase difference pixel in the peripheral portion 11bR on the right side of the light receiving region has an opening area larger than those in the central portion 11a and the peripheral portion 11bL on the left side. [Selection] Figure 8

Description

  The present invention relates to a solid-state imaging device having asymmetric pixels used for focus detection and the like.

  Camera modules installed in digital cameras and mobile devices such as mobile phones and smartphones are almost equipped with an autofocus function. A plurality of methods for realizing autofocus are known. For example, in recent digital cameras and camera modules, contrast detection type autofocus (so-called contrast AF) that performs focus adjustment so that the contrast of an image is maximized. In addition, a phase difference detection type autofocus (hereinafter referred to as phase difference AF) that performs focus adjustment based on a phase difference due to parallax is often used.

  For the phase difference AF, for example, as in the solid-state imaging device described in Patent Document 1, light incident from a left or right direction is selectively received at a predetermined position in a light receiving region in which a plurality of pixels are arranged. In order to detect the phase difference, a solid-state imaging device having focus detection pixels (hereinafter referred to as phase difference pixels) formed in an asymmetric shape in the left-right direction is used (Patent Document 1).

  By the way, in recent digital cameras and camera modules, the back focus tends to be shortened due to demands for miniaturization and thinning. In addition, a solid-state imaging device having a large light receiving area has been mounted on a small and thin digital camera or the like. As described above, when the back focus is shortened or a solid-state imaging device having a large light receiving area with respect to the back focus is employed, the incident angle of light to the peripheral portion of the solid-state imaging device increases.

  Since the pixels of the solid-state imaging device are formed so that light incident from the front is generally efficiently collected and photoelectrically converted, the sensitivity decreases as the light incident angle increases. For this reason, when the incident angle of light to the pixels in the periphery of the light receiving region is large, shading may occur in luminance and color in the captured image. In order to reduce shading, it is only necessary to equalize the sensitivity of the pixels at the central portion and the peripheral portion in consideration of the incident angle of light to the peripheral portion. For this reason, for example, by arranging (scaling) the microlenses provided in each pixel closer to the center as the pixels in the peripheral part increase the light collection efficiency of the pixels in the peripheral part, There is known a technique for reducing the shading by relaxing the sensitivity difference between the pixels of the part.

  In addition, by increasing the pixel aperture from the center to the periphery of the solid-state imaging device, or by reducing the pixel aperture from the periphery to the center, the sensitivity of the center and the periphery is made uniform and shading is performed. The technique to reduce is also known (patent document 2).

  Furthermore, in a solid-state imaging device having phase difference pixels, the signal level of each phase difference pixel can be made uniform by making the pupil region of the phase difference pixel in the central portion smaller than that in the peripheral portion, and conversely A technique for improving the accuracy of the phase difference AF by making the pupil region of the phase difference pixels in the peripheral part smaller than that in the central part and making the vignetting of each phase difference pixel uniform (patent) Reference 3).

JP 2012-003009 A JP 2004-056407 A JP 2010-039106 A

  For example, the phase difference pixel is formed in an asymmetrical structure on the left and right sides, so that it is more sensitive to the incident angle of light than the normal pixel, and the phase difference pixel in the peripheral portion has a lower sensitivity than the normal pixel. . For example, the sensitivity of the normal pixel is made uniform by, for example, microlens scaling. However, as described above, the amount of decrease in the sensitivity of the phase difference pixel in the peripheral portion is larger than that of the normal pixel. In the lens scaling, the sensitivity of the phase difference pixels cannot be sufficiently compensated, and when the phase difference pixels in the peripheral part are used, the accuracy of the phase difference AF may be poor.

  For this reason, in order to perform accurate phase difference AF even when using peripheral phase difference pixels, the aperture of the peripheral phase difference pixels and the size of the pupil region are adjusted according to Patent Documents 2 and 3, for example. It is desirable to improve the sensitivity of the peripheral phase difference pixels.

  However, since the phase difference pixels are formed in a left-right asymmetric structure, for example, the accuracy of the phase difference AF can be achieved even if the apertures of the phase difference pixels in the peripheral portion are uniformly increased as in Patent Documents 2 and 3. May not improve. Specifically, a phase difference pixel that selectively receives light that has reached the right side of incident light (hereinafter referred to as a right phase difference pixel) is located on the left side with respect to the center of the light receiving region. Although the sensitivity is low, the sensitivity at the peripheral part on the right is rather high. Conversely, a phase difference pixel (hereinafter referred to as a left phase difference pixel) that selectively receives light that has reached the left side of the incident light has a low sensitivity in the right side peripheral part, but in the left side peripheral part. Some have high sensitivity. Therefore, as in Patent Documents 2 and 3, even if the size of the aperture or pupil region is adjusted in the peripheral portion, the aperture of the phase difference pixel or the like is not distinguished without distinguishing between the right phase difference pixel and the left phase difference pixel. If the size is uniformly adjusted, the S / N is deteriorated in the case where the sensitivity is originally high, so that the accuracy of the phase difference AF is not necessarily improved.

  Also, by increasing the gain when reading the pixel value than when reading the pixel value of the normal pixel, the pixel value of the phase difference pixel in the peripheral area with low sensitivity is increased, and the sensitivity of each phase difference pixel is made uniform However, increasing the readout gain also increases the noise component included in the pixel value, so the S / N is not improved. In particular, because the light incident angle is large, light that should be incident on adjacent pixels may enter the neighboring pixels and color mixing may occur. However, if the readout gain is increased, the signal value due to color mixing also increases. Therefore, the accuracy of the phase difference AF cannot be sufficiently improved only by increasing the gain when reading the pixel values of the peripheral phase difference pixels with low sensitivity.

  In addition to this, it is conceivable to improve the sensitivity of the peripheral phase difference pixels by making the microlens scaling amount different between the normal pixels and the phase difference pixels. If the scaling amount of the microlens is changed between the phase difference pixel and the phase difference pixel, a color gap may increase due to a gap between the microlens of the normal pixel and the phase difference pixel.

  The present invention improves the sensitivity of the low-sensitivity phase difference pixels in the peripheral part of the light receiving region without degrading the image quality of the photographed image, so that the accurate phase difference can be obtained even when the peripheral phase difference pixels are used. The purpose is to enable AF.

  The solid-state imaging device of the present invention includes a plurality of normal pixels, first phase difference pixels, and second phase difference pixels in a light receiving region where an image of a subject is formed. A normal pixel receives incident light isotropically. The first phase difference pixel is a pixel having an opening that is eccentrically arranged in a first direction (for example, the right direction), and selectively receives light reaching the first direction side of incident light. The second phase difference pixel is a pixel having an opening eccentrically arranged in a second direction (for example, the left direction) opposite to the first direction, and selects light that has reached the second direction side from incident light. Receive light. The first phase difference pixel in the peripheral portion on the second direction side has an area of the first opening with respect to the first phase difference pixel in the central portion of the light receiving region and the peripheral portion on the first direction side. large. Conversely, the second phase difference pixel in the peripheral portion on the first direction side has a larger area of the second opening than the second phase difference pixel in the peripheral portion on the central portion and the second direction side.

  In the first phase difference pixel in the peripheral portion on the second direction side, the first opening is preferably extended to the second direction side with respect to the central portion in order to enlarge the opening area. In addition, in the second phase difference pixel in the peripheral portion on the first direction side, the second opening may be extended to the first direction side with respect to the central portion in order to enlarge the opening area. preferable.

  In the first phase difference pixel in the peripheral portion on the second direction side, the center position of the first opening is preferably on the second direction side with respect to the central portion. In the second phase difference pixel in the peripheral portion on the first direction side, the center position of the second opening is preferably on the first direction side with respect to the central portion.

  The first phase difference pixel in the peripheral portion on the second direction side and the second phase difference pixel in the peripheral portion on the first direction side have a photodiode for photoelectric conversion more than that in the central portion. Small is preferable.

  The area of the first opening may be expanded stepwise from the central part to the peripheral part on the second direction side, and the area of the second opening may be expanded stepwise from the central part to the peripheral part on the first direction side.

  When the first phase difference pixel and the second phase difference pixel are provided in a plurality of colors, the first opening of the first phase difference pixel in the peripheral portion on the second direction side, and the first direction pixel It is preferable that each magnification of the second opening of the second phase difference pixel in the peripheral portion on the side is determined for each color.

  When the image of the subject is formed on the light receiving area by the zoom lens, the side in the second direction depends on the incident angle of the incident light when the focal length of the zoom lens is the longest and the shortest. It is preferable that each area of the first opening of the first phase difference pixel in the peripheral part of the first phase difference and the second opening of the second phase difference pixel in the peripheral part on the first direction side is determined.

  Further, in the first phase difference pixel in the peripheral portion on the first direction side, the first opening is made smaller than that in the first phase difference pixel in the central portion, and the second phase position in the peripheral portion on the second direction side. In the phase difference pixel, the second opening may be made smaller than the second phase difference pixel in the center.

  In the case where each pixel is provided with a microlens that collects incident light, it is preferable that the microlenses in the peripheral portion are arranged eccentrically in the direction of the center portion according to the incident angle of the incident light to each pixel. .

  In another solid-state imaging device of the present invention, there are no normal pixels, and all the pixels are composed of the phase difference pixels of the first phase difference pixel or the second phase difference pixel.

  According to the present invention, the opening of the right phase difference pixel is enlarged at the left side peripheral portion, and the right side peripheral portion is the same (or reduced) as that at the central portion. Since the enlargement is performed at the right peripheral part and the left peripheral part is the same (or reduced) as the central part, the sensitivity of the left and right phase difference pixels can be appropriately compensated to improve the accuracy of the phase difference AF. it can. In addition, since the size of the aperture of the phase difference pixel is adjusted regardless of the scaling of the microlens or the like, the image quality of the captured image is not degraded.

It is explanatory drawing which shows a solid-state imaging device. It is explanatory drawing which shows the arrangement | sequence of a color filter. It is sectional drawing which shows the structure of a normal pixel and a phase difference pixel. It is explanatory drawing which shows the incident angle of the light of the center part of a light-receiving region, and a peripheral part. It is sectional drawing which shows the incident light to the normal pixel according to a position. It is sectional drawing which shows the incident light to the right phase difference pixel in case an opening area does not depend on a position. It is a graph showing the specific sensitivity of the right phase difference pixel according to the position when the opening area does not depend on the position. It is sectional drawing which shows the incident light to the right phase difference pixel at the time of expanding an opening in the peripheral part on the left side. It is a graph showing the opening area of the right phase difference pixel according to the position when opening is expanded in the peripheral part on the left side. It is a graph showing the specific sensitivity of the right phase difference pixel according to a position. It is a graph at the time of aligning the specific sensitivity of the right phase difference pixel of the peripheral part of the left side with the thing of a center part. Furthermore, it is a graph which shows the opening area according to the position at the time of reducing the opening area of the right phase difference pixel in the right peripheral part. It is a graph at the time of making a specific sensitivity constant in a center part and a peripheral part. It is a graph which shows the opening area of the left phase difference pixel according to a position. It is a graph which shows the sensitivity ratio of the left phase difference pixel according to a position. It is explanatory drawing showing the expansion method of the opening area of a phase difference pixel. It is explanatory drawing showing another method to expand the opening area of a phase difference pixel. It is explanatory drawing in the case of making PD of a phase difference pixel small in a peripheral part. It is explanatory drawing which shows the example which subdivides a light reception area | region. It is a graph showing the change of the opening area according to the position in the case of expanding the opening area of a phase difference pixel in steps. It is explanatory drawing showing phase difference pixels other than G pixel. It is explanatory drawing which shows the solid-state imaging device of a honeycomb arrangement | sequence. It is explanatory drawing which shows the solid-state imaging device of the other honeycomb arrangement | sequence from which a color arrangement | sequence differs. It is explanatory drawing which shows the solid-state imaging device of which a color filter is a Bayer arrangement. It is explanatory drawing which shows the solid-state imaging device which made all the pixels the phase difference pixel.

  As shown in FIG. 1, the solid-state imaging device 10 is a CMOS image sensor, and includes a light receiving region 11, a vertical scanning circuit 13, a horizontal scanning circuit 14, an output circuit 16, a control circuit 17, and the like.

  The light receiving region 11 is a region in which a plurality of pixels 21 are squarely arranged along the horizontal direction (X direction) and the vertical direction (Y direction). An image of a subject is formed in the light receiving region 11 by an imaging lens (see FIG. 3), and each pixel 21 accumulates a charge corresponding to the amount of incident light by photoelectric conversion.

  The pixel 21 includes a photodiode (hereinafter referred to as PD) 22, a reset transistor (hereinafter referred to as Tr) 23, an amplifier transistor (hereinafter referred to as Ta) 24, and a selection transistor (hereinafter referred to as Ts) 25. Tr23, Ta24, and Ts25 are, for example, n-type MOS transistors. Each pixel 21 is provided with a color filter 41 (see FIG. 2) of any one of red (R), green (G), and blue (B). Photoelectrically converts the color light of the corresponding color filter 41.

  The pixel 21 arranged in the light receiving region 11 is one of two types of pixels, a normal pixel and a phase difference pixel. The normal pixel and the phase difference pixel have different three-dimensional structures (specifically, the size and position of the opening with respect to the PD 22), but the electrical configuration is the same. For this reason, in FIG. 1, all the pixels in the light receiving region 11 are the pixels 21 without distinguishing between the normal pixels and the phase difference pixels.

  The normal pixel is a pixel 21 formed symmetrically in the horizontal direction and the vertical direction, and an imaging signal based on the charge accumulated in the normal pixel is used for forming a captured image. Most of the pixels 21 are normal pixels.

  The phase difference pixel is formed in an asymmetric shape in the horizontal direction to selectively receive light incident from either the left or right direction, and the phase difference pixel (selectively receives light incident from the right direction) Hereinafter, a phase difference pixel (hereinafter referred to as a phase difference pixel) and a phase difference pixel (hereinafter referred to as a phase difference B pixel) that selectively receives incident light from the left direction as a set, and a plurality of sets of phase difference pixels are included in the light receiving region 11. It is evenly provided inside. That is, the phase difference pixels are provided in the central portion and the peripheral portion of the light receiving region 11. An imaging signal based on the charge accumulated in the phase difference pixel is used for phase difference AF.

  The PD 22 is an element that generates a charge corresponding to the amount of incident light by photoelectric conversion. The anode is connected to the ground, and the cathode is connected to the gate electrode of Ta24. A connection portion between the cathode of the PD 22 and the gate electrode of the Ta 24 is a floating diffusion (not shown; hereinafter referred to as FD), and charges generated by the PD 22 are stored therein.

  In Tr23, the source electrode is connected to the FD, and the power supply voltage VDD (not shown) is applied to the drain electrode. The gate electrode of Tr 23 is connected to the reset line 26. The Tr 23 is turned on when a reset pulse is applied from the vertical scanning circuit 13 to the gate electrode via the reset line 26. When the Tr 23 is turned on, the power supply voltage VDD is applied to the FD, and the charges accumulated in the FD are discarded.

  In Ta24, the gate electrode is connected to the FD, and the power supply voltage VDD is applied to the drain electrode. The source electrode from which the signal voltage is output is connected to the drain electrode of Ts25. The Ta 24 outputs a signal voltage corresponding to the amount of charge accumulated in the FD to the source electrode.

  The drain electrode of Ts25 is connected to the source electrode of Ta24, and the source electrode is connected to the signal line 27. The gate electrode of Ts25 is connected to the row selection line 28. Ts 25 is turned on when a selection pulse is input from the vertical scanning circuit 13 via the row selection line 28, and outputs a signal voltage output from the Ta 24 to the signal line 27.

  The vertical scanning circuit 13 is a driving circuit for the pixels 21, and a reset line 26 and a row selection line 28 for each row are connected to each other. The vertical scanning circuit 13 inputs a reset pulse to the reset line 26 of the selected row. Further, a selection pulse is input to the row selection line 28 to control the operation of Tr23 and Ts25. As a result, the pixel 21 is operated as described above.

  The horizontal scanning circuit 14 selects a column from which a signal voltage is read by turning on one of the column selection transistors (Tc) 32 provided on each signal line 27.

  The signal line 27 is a wiring for reading a signal voltage from each pixel 21, and is provided for each column of the pixels 21. A correlated double sampling (CDS) circuit 31 and a column selection transistor (Tc) 32 are provided at the end of the signal line 27. The CDS circuit 31 operates based on the clock signal input from the control circuit 17 and is a voltage signal so that noise associated with readout is removed from the pixels 21 on the row selection line 28 selected by the vertical scanning circuit 13. Is sampled and held. The voltage signal held by the CDS circuit 31 is output to the output circuit 16 via the output bus line 33 when the column selection transistor 67 is turned on by the horizontal scanning circuit 14.

  The output circuit 16 includes an amplifier 34 that amplifies the voltage signal input from the CDS 31 and an A / D conversion circuit 35 that converts the voltage signal amplified by the amplifier 34 into digital data. The gain of the amplifier 34 is variable and is appropriately adjusted according to the setting such as the shooting mode.

  The control circuit 17 is connected to each part of the solid-state imaging device 10 such as the vertical scanning circuit 13 and the horizontal scanning circuit 14, and comprehensively controls each part of the solid-state imaging device 10. For example, the operations of the vertical scanning circuit 13 and the horizontal scanning circuit 14 operate based on a control signal such as a clock signal input from the control circuit 17. The operation of the CDS 31 and the gain of the amplifier 34 are also controlled by the control circuit 17.

  As shown in FIG. 2, the color filter 41 of the solid-state imaging device 10 has a long periodicity with a color arrangement of 6 × 6 pixels as one unit. More specifically, the color filter 41 is an array in which two types of subunits 41a and 41b each having a color array of 3 × 3 pixels are arranged at diagonal positions. In the first subunit 41a, a green (G) filter is arranged at the center and diagonal positions of 3 × 3 pixels, a blue (B) filter is arranged at the center of the left and right, and a red (R) filter is arranged at the center of the top and bottom. Is a unit. The second subunit 41b is the same as the first subunit 41a in that G filters are arranged at the center and diagonal positions of 3 × 3 pixels, but the B filter and the R filter are different from the first subunit 41a. Are reversed, an R filter is arranged at the center of the left and right, and a B filter is arranged at the center of the top and bottom.

  For example, the color filter 41 has a long periodicity as compared with a Bayer arrangement in which the color arrangement of 2 × 2 pixels is one unit. Therefore, the solid-state imaging device 10 suppresses the occurrence of moire even without using an optical low-pass filter. be able to. Further, in the solid-state imaging device 10 employing the color filter 41, since RGB pixels always exist in the vertical direction (vertical direction) and the horizontal direction (horizontal direction), false colors can be suppressed and accurate color reproduction is possible. is there.

  The pair of left and right phase difference pixels 42a and 42b are pixels for obtaining a signal including information related to parallax for phase difference AF. For example, each of the first subunit 41a at the upper right and the second subunit 41b at the upper left It is formed in the lower left G pixel. Pixels other than the phase difference pixels 42a and 42b are normal pixels 43 for obtaining a captured image of the subject.

  In the normal pixel 43, the openings 55 are formed symmetrically in the vertical and horizontal directions, and receive light that is incident from each of the vertical and horizontal directions equally (isotropically). On the other hand, the phase difference pixel 42a is a right phase difference pixel that selectively receives light that has reached the right side of the PD 22 among incident light, and the opening 56R is smaller than the opening 55 of the normal pixel 43, and is located to the right. It is arranged eccentrically. The phase difference pixel 42b is a left phase difference pixel that selectively receives light that has reached the left side of the PD 22 among incident light, and the opening 56L is smaller than the opening 55 of the normal pixel 43 and is eccentrically arranged to the left. ing.

  The voltage signals output from the phase difference pixels 42a and 42b are signals having left and right parallax, respectively, and the voltage signal having this parallax (or a pixel value based on this voltage signal) is used for the phase difference AF. Further, when a captured image is generated from the voltage signal of each pixel output from the solid-state imaging device 10, the voltage signal of the phase difference pixels 42 a and 42 b is multiplied by a predetermined amount, for example, and used with the sensitivity matched to the normal pixel 43. In some cases, the pixel values at the positions of the phase difference pixels 42a and 42b are generated by interpolation based on the voltage signal of the G pixel (normal pixel 43) around the phase difference pixels 42a and 42b.

  The phase difference pixels 42 a and 42 b are provided on the entire surface of the light receiving region 11. However, the phase difference pixels 42 a and 42 b are not necessarily provided in the 6 × 6 pixel unit of the color filter 41. When each pixel is viewed in the unit of 6 × 6 pixels of the color filter 41, there are units in which the phase difference pixels 42a and 42b are not provided, and in the case where the phase difference pixels 42a and 42b are provided, 6 × 6 pixel units. It is provided at the above location. In the unit in which the phase difference pixels 42 a and 42 b are not provided, all are normal pixels 43.

  As shown in FIG. 3, the solid-state imaging device 10 is a back side illuminated (BSI) CMOS image sensor, and includes a support substrate 51, a wiring layer 52, a p-type semiconductor substrate 53, a light shielding layer 54, and a color filter. 41, a microlens 57, and the like. The side on which the wiring layer 52 is provided with respect to the p-type semiconductor substrate 53 is the “front surface” of the solid-state imaging device 10, and the side on which the color filter 41, the light shielding layer 54, and the microlens 57 are provided is the “back surface”. . Light enters the solid-state imaging device 10 from the back side through the microlens 57, the color filter 41, and the light shielding layer 54. FIG. 3 schematically shows a cross section of the solid-state imaging device 10 in the central portion 11a (see FIG. 4) of the light receiving region 11.

  The support substrate 51 is, for example, a silicon substrate, and exposes the back surface of the p-type semiconductor 53 in the process of manufacturing the back-illuminated solid-state imaging device 10, and the surface of the wiring layer 52 to thin the p-type semiconductor 53. To be joined.

  The wiring layer 52 is formed on the surface of the p-type semiconductor substrate 53, and the transistors (Tr23, Ta24) that form each pixel 21 (the normal pixel 43 and the phase difference pixels 42a, 42b) by the wiring 52a provided in the wiring layer 52. , Ts25), various circuits such as a vertical scanning circuit 13, a horizontal scanning circuit 14, a control circuit 17, an output circuit 16, a control circuit 17, and a CDS 31 for driving each pixel 21, a reset line 26, a signal line 27, a row Various wirings such as a selection line 28 and an output bus line 33 are formed.

  The PD 22 is formed by a PN junction of a p-type semiconductor substrate 53 and an n-type semiconductor region formed in the p-type semiconductor substrate 53. The p-type semiconductor substrate 53 is thinned, and the photoelectric conversion region of the PD 22 indicated by a broken line reaches the vicinity of the back surface of the p-type semiconductor substrate 53. The charges generated by the photoelectric conversion of the PD 22 are accumulated in the vicinity of the interface with the wiring layer 52. Each PD 22 is separated by a separation layer (for example, p ++ layer) not shown.

  The light shielding layer 54 is provided on the back surface side of the p-type semiconductor substrate 53 and suppresses color mixing by shielding light incident between the PDs 22. The light shielding layer 54 is formed of, for example, a metal thin film and has openings 55 and 56 corresponding to the PDs 22. The openings 55 and 56 are filled with, for example, a transparent material, and the back surface of the light shielding layer 54 (interface with the color filter 41) is flat.

  The opening 55 is provided corresponding to the normal pixel 43, and has a size that exposes almost the entire surface of the PD 22 of the normal pixel 43. For this reason, as indicated by the alternate long and short dash line, in the normal pixel 43, almost the entire light flux of the light incident through the corresponding microlens 57 and the color filter 41 is incident on the PD 22 through the opening 55. The opening 55 has the same size in all the normal pixels 43 regardless of the position of the normal pixels 43 and the like. For this reason, all the normal pixels 43 have the same light receiving area regardless of the position in the light receiving region 11 (see FIG. 4).

  On the other hand, the opening 56L is provided corresponding to the left phase difference pixel 42b, and has a narrower width and a smaller opening area than the opening 55 for the normal pixel 43. Further, the opening 56L is eccentrically arranged on the left side (X direction negative side). For this reason, the phase difference pixel 42b receives only a part of the light beam that enters through the corresponding microlens 57 and the color filter 41 and reaches the left side of the PD 22 through the opening 56L.

  In FIG. 3, only the left phase difference pixel 42b is shown among the phase difference pixels 42a and 42b, but the configuration of the right phase difference pixel 42a is the same as that of the left phase difference pixel 42b, and thus illustration is omitted. However, in the right phase difference pixel 42a, contrary to the left phase difference pixel 42b, the opening 56R is eccentrically arranged on the right side (X direction positive side), and enters through the corresponding microlens 57 and the color filter 41. Of the light, only a part of the light beam that reaches the right side of the PD 22 through the opening 56R is received.

  Each color segment of the color filter 41 is provided so as to correspond to the PD 22, and the center of each color segment is at a position corresponding to the center of the PD 22. The arrangement of the color filter 41 is as described above, and the light beam condensed by the microlens 57 passes through the color filter 41 and becomes one of R, G, and B and enters the PD 22.

  The micro lens 57 is provided on the color filter 41 so as to correspond to each PD 22 and has a substantially hemispherical shape. The microlens 57 collects incident light on the corresponding PD 22. At the center of the light receiving region 11 (center of the central portion 11a), the center of the microlens 57 substantially coincides with the center of the PD 22. However, the microlens 57 is also arranged (scaled) in the central portion 11 a while being offset in the central direction of the light receiving region 11 according to the principal ray angle 45.

  As shown in FIG. 4, the solid-state imaging device 10 is used together with the imaging lens 44, and an image of a subject 59 is formed on the light receiving region 11 of the solid-state imaging device 10 by the imaging lens 44. In FIG. 4, the imaging lens 44 is schematically formed as one lens, but the imaging lens 44 may be configured by a single lens or may be configured by a plurality of lenses. That is, the specific configuration of the imaging lens 44 is arbitrary as long as the image of the subject 59 can be formed on the light receiving region 11. For this reason, the imaging lens 44 may include various optical filters such as an infrared filter and an optical element having substantially no lens action.

  When an image of the subject 59 is formed on the light receiving region 11 by the imaging lens 44, the chief ray angle (hereinafter referred to as chief ray angle) 45 indicated by a one-dot chain line is from the central portion 11a of the light receiving region 11 to the left and right peripheral portions 11bR. , Gradually increases over 11 bL. For this reason, the solid-state imaging device 10 has a structure in which each pixel is matched with the principal ray angle 45 at each location.

  First, as shown in FIG. 5, in the solid-state imaging device 10, the microlens 57 is scaled according to the principal ray angle 45. Specifically, the structure below the color filter 41 is the same in both the central portion 11a and the peripheral portions 11bR and 11bL. However, in the peripheral portions 11bR and 11bL, the center position of each microlens 57 is the central portion 11a. It is arranged eccentric to the side. For example, the light flux of incident light to each normal pixel 43 is divided into a right half light flux (hereinafter referred to as a right light flux) indicated by a broken line arrow and a left half light flux (hereinafter referred to as a left light flux) indicated by a solid arrow. Then, in the normal pixel 43 in the central portion 11a, the left light beam is condensed on the right side of the PD 22 and the right light beam is condensed on the left side of the PD 22 by the micro lens 75. That is, in the normal pixel 43 in the central portion 11a, almost all of the incident light beam is collected on the PD 22.

  Further, in the normal pixel 43 in the right peripheral portion 11bR, the chief ray is inclined as shown by the alternate long and short dash line, but since the microlens 75 is scaled according to the angle of the chief ray, the left luminous flux is also All the right side light flux is also condensed on PD22. Similarly, the same applies to the normal pixels 43 in the left peripheral portion 11bL. Since the microlens 75 is scaled according to the angle of the principal ray, both the left beam and the right beam are condensed on the PD 22. . Therefore, the normal pixel 43 can receive almost all of the incident light beam by the PD 22 in any of the central portion 11a, the right peripheral portion 11bR, and the left peripheral portion 11bL.

  Further, in the solid-state imaging device 10, the areas (opening areas) of the openings 56 </ b> L and 56 </ b> R of the phase difference pixels 42 a and 42 b are adjusted according to the position in the light receiving region 11.

  First, for comparison, the openings 56L and 56R of the phase difference pixels 42a and 42b have the same size in each of the central portion 11a, the right peripheral portion 11bR, and the left peripheral portion 11bL (half the opening 55 of the normal pixel 43). The case of (area) is described. In this case, as shown in FIG. 6, since the left half of the right phase difference pixel 42a in the central portion 11a is shielded from light, only light that reaches the right side of the PD 22 through the opening 56R is selectively received. . For example, if approximately 1/5 of the left beam and approximately 4/5 of the right beam reach the right side of the PD 22, the amount of light received by the right phase difference pixel 42a in the central portion 11a is approximately 1/2 of the incident light amount. is there.

  On the other hand, in the right phase difference pixel 42a in the right peripheral portion 11bR, among the incident light beams, the right light beam (broken arrow) having a small incident angle is mostly shielded and the left light beam (solid line arrow) having a large incident angle. ) Almost reaches the PD 22. For example, if approximately 1/5 of the right beam and almost all of the left beam reach the right side of the PD 22, the amount of light received by the right phase difference pixel 42a in the right peripheral portion 11bR is approximately 3/5 of the incident light amount. is there.

  On the other hand, in the right phase difference pixel 42a in the left peripheral portion 11bL, the incident angle of the right light beam (broken arrow) is large in the incident light beam, contrary to that in the right peripheral portion 11bR. The incident angle of (solid line arrow) is small. For this reason, in the right phase difference pixel 42a in the left peripheral portion 11bL, almost all of the right beam is blocked and a part of the left beam reaches the PD 22. For example, if about 4/5 of the left light beam reaches the PD 22, the amount of light received by the right phase difference pixel 42a in the peripheral portion 11bL is about 2/5 of the incident light amount.

  Accordingly, as shown in FIG. 7, the specific sensitivity of the right phase difference pixel 42a (sensitivity to the sensitivity of the normal pixel 43) is substantially proportional to the position in the X direction, and the right peripheral portion 11bR is more than the central portion 11a. Although larger, the left peripheral portion 11bL is smaller than that of the central portion 11a. For this reason, when the right phase difference pixel 42a of the right peripheral portion 11bR having high specific sensitivity is used, the phase difference AF can be performed with higher accuracy than when the right phase difference pixel 42a of the central portion 11a is used. When the right phase difference pixel 42a in the left peripheral portion 11bL whose sensitivity is smaller than that of the central portion 11a is used, the accuracy of the phase difference AF is not good.

  For this reason, as shown in FIGS. 8 and 9, in the solid-state imaging device 10, the opening 56 </ b> R of the right phase difference pixel 42 a in the peripheral portion 11 b </ b> L on the left side from the center of the light receiving region 11 (the center of the central portion 11 a) is centered. The area is larger than the opening 56R of the portion 11a and the right peripheral portion 11bR. As described above, when the opening area is larger than that of the central portion 11a and the right peripheral portion 11bR, the sensitivity of the right phase difference pixel 42a in the left peripheral portion 11bL is set to the sensitivity of the right phase difference pixel 42a in the central portion 11a. It can be improved beyond sensitivity.

  For example, when the opening area is the same as that of the central portion 11a (see FIG. 6), the left light beam (solid arrow) that is partially shielded from light is almost all when the opening area is enlarged (see FIG. 8). Reaches PD22. Further, when the opening area is the same as that of the central portion 11a, the right light beam (broken arrow) that has been shielded from light passes through the opening 56R having an enlarged area and reaches the PD 22. For this reason, if approximately 1/5 of the right light beam reaches the PD 22, the amount of light received by the phase difference pixel 42a of the left peripheral portion 11bL having the opening 56R whose area is enlarged is about 3/5 of the incident light amount. improves. This is substantially the same amount of received light as that of the right phase difference pixel 42a in the right peripheral portion 11bR.

  For example, as shown in FIG. 10, the magnification of the opening 56 </ b> R in the left peripheral portion 11 b </ i> L is symmetric between the left peripheral portion 11 b </ i> L from the center of the light receiving region 11 and the right peripheral portion 11 b </ i> R from the center. In this way, the adjustment may be made according to the position of each right phase difference pixel 42a. The enlargement ratio of the opening 56R in the left peripheral portion 11b is such that the specific sensitivity of the right phase difference pixel 42a in the left peripheral portion 11bL is at least equal to or greater than the specific sensitivity of the right phase difference pixel 42a in the central portion 11a. In particular, as shown in FIG. 11, the enlargement ratio of the opening 56R is adjusted so that the specific sensitivity is constant from the center of the light receiving region 11 to the left peripheral portion 11bL as shown in FIG. preferable. As described above, when the enlargement ratio of the opening 56R is adjusted so that the specific sensitivity at the center and the specific sensitivity of the left peripheral portion 11bL are equal, the right phase difference pixel 42a of the left peripheral portion 11bL should originally receive light. This is because the left light beam (signal) is large and the amount of light received by the right light beam that causes noise is small, so that the S / N is particularly good while the specific sensitivity is high.

  As shown in FIG. 12, the opening 56R of the right phase difference pixel 42a in the right peripheral portion 11bR may be smaller than that in the central portion 11a. The reduction ratio of the opening 56R in the right peripheral portion 11bR is preferably adjusted so that the specific sensitivity is constant from the center of the light receiving region 11 to the right peripheral portion 11bR as shown in FIG. As described above, when the area of the opening 56R is adjusted so that the specific sensitivity at the center of the light receiving region 11 and the specific sensitivity of the right peripheral portion 11bR are equal, it is compared with the case where the opening area is the same as that at the center. Although the specific sensitivity decreases, the S / N can be improved. Further, as can be seen from the above description, as shown in FIG. 13, the area of the opening 56R is adjusted so that the specific sensitivity is substantially equal in the central portion 11a, the left peripheral portion 11bL, and the right peripheral portion 11bR. Needless to say, is particularly preferable.

  The left phase difference pixel 42b is bilaterally symmetric with the right phase difference pixel 42a. Therefore, as shown in FIG. 14, the left phase difference pixel 42b has a large area of the opening 56L at least from the center of the light receiving region 11 to the right peripheral portion 11bR, contrary to the case of the right phase difference pixel 42a described above. The opening area is adjusted so that

  As shown in FIG. 15, when the opening area of the left phase difference pixel 42b is constant, the specific sensitivity of the left phase difference pixel 42b in the right peripheral portion 11bR is lower than that in the central portion 11a (the one-dot chain line). ). However, as described above, by expanding the opening area of the left phase difference pixel 42b in the right peripheral portion 11bR, the same as the left phase difference pixel 42b in the left peripheral portion 11bL (solid line), or the center The specific sensitivity of the left phase difference pixel 42b in the right peripheral portion 11bR is improved to the same extent as that in the center of the portion 11a (broken line).

  As described above, in the solid-state imaging device 10, the opening 56R of the right phase difference pixel 42a is enlarged at the left peripheral portion 11bL, and the right peripheral portion 11bR is the same as or reduced at the central portion 11a. Similarly, the opening 56L of the left phase difference pixel 42b is enlarged at the right peripheral portion 11bR, and the left peripheral portion 11bL is the same as or reduced at the central portion 11a. As described above, since the solid-state imaging device 10 adjusts the opening area according to the position of the left and right phase difference pixels 42a and 42b, respectively, the sensitivity of the left and right phase difference pixels is appropriately compensated for, and the phase difference AF Accuracy can be improved.

  For example, when the aperture area is uniformly enlarged according to the distance from the center of the light receiving region 11 without distinguishing the left and right phase difference pixels 42a and 42b, the phase difference pixel (right side In the right phase difference pixel 42a in the peripheral portion and the left phase difference pixel 42b in the left peripheral portion 11bL), the amount of received light of the light beam that becomes noise increases, so the S / N deteriorates and the phase difference is high even if the specific sensitivity is high. The accuracy of AF may deteriorate. Compared to this case, the solid-state imaging device 10 adjusts the sizes of the openings 56L and 56R according to the positions of the left and right phase difference pixels 42a and 42b, respectively, so that the S / N is not deteriorated. The accuracy of phase difference AF can be improved reliably.

  In addition, when the microlens 75 of the phase difference pixels 42a and 42b is scaled differently from the normal pixel 43, color mixing may occur and the image quality of the captured image may be impaired. Since the accuracy of the phase difference AF is improved only by adjusting the aperture areas of the phase difference pixels 42a and 42b regardless of the scaling 75, the image quality of the captured image is not impaired.

  When the opening area of the right phase difference pixel 42a is adjusted as described above, for example, as shown in FIG. 16, in the left peripheral portion 11bL, the opening 56R of the right phase difference pixel 42a in the central portion 11a is compared. The area may be enlarged by moving the left side position of the right phase difference pixel 42a to the left and expanding it to the side of the opening 56R. As described above, when the aperture is expanded laterally with the right side of the aperture 56R of the right phase difference pixel 42a in the central portion 11a being aligned, and the area is expanded, both S / N and specific sensitivity are improved. Easy to make. In this case, even if the opening area is enlarged, the base line length (the center distance between the phase difference pixels 42a and 42b) is not easily shortened, so that information on parallax can be easily obtained. In FIG. 16, the right phase difference pixel 42a is taken as an example, but the same applies to the left phase difference pixel 42b. In the right peripheral portion 11bR, the left side position is aligned with that of the central portion 11a, and the right side position is set to the right side. The area may be enlarged by moving to and expanding the opening 56L horizontally.

  On the other hand, as shown in FIG. 17, in the right phase difference pixel 42a of the left peripheral portion 11bL, the right side and the left side of the opening 56R of the right phase difference pixel 42a of the central portion 11a are both moved to the left side to enlarge the opening area. You may do it. In this case, the center position of the opening 56R also moves to the left. As described above, when the positions of the right side and the left side of the opening 56R are both moved to the left side in order to enlarge the opening area, almost all the left light beam that becomes a signal is received while the width of the opening 56R is kept as small as possible. In addition, the opening area can be enlarged so as to prevent the incidence of the right light beam that becomes noise. For this reason, as compared with the case where the right side is not moved, the increase in specific sensitivity is small and the base line length tends to be short, but the S / N is particularly good. In FIG. 17, the right phase difference pixel 42a is taken as an example, but the same applies to the left phase difference pixel 42b.

  In addition, after adjusting the opening area of the right phase difference pixel 42a in the peripheral portion 11bL as described above, the PD 22 of the right phase difference pixel 42a in the peripheral portion 11bL is changed to the PD 22 in the central portion 11a as shown in FIG. However, it may be made smaller. When the PD 22 of the right phase difference pixel 42a in the peripheral part 11bL is reduced in this way, the distance of the PD 22 of the right phase difference pixel 42a from the PD 22 of the peripheral normal pixel 43 increases. When the distance between the PD 22 of the normal pixel 43 and the PD 22 of the right phase difference pixel 42a is short, light obliquely incident on the normal pixel 43 may leak into the PD 22 of the right phase difference pixel 42a and color mixing may occur. As described above, if the PD 22 of the right phase difference pixel 42a is made small, even if light obliquely incident on the normal pixel 43 leaks to the phase difference pixel 42a side, it is difficult to reach the PD 22 of the right phase difference pixel 42a. Color mixing is more reliably prevented, and a signal with good S / N is easily obtained.

  As described above, when the PD 22 of the right phase difference pixel 42a in the peripheral portion 11bL is made small, the area of the opening 56R and the size and shape of the PD 22 may be appropriately determined so that the specific sensitivity and S / N are optimized. good. The size and shape of the PD 22 may be a rectangle that matches the enlarged opening 56R of the right phase difference pixel 42a. For example, a rectangular shape whose size and shape substantially match the opening 56R of the right phase difference pixel 42a may be used. The same applies to the left phase difference pixel 42b.

  In the above-described embodiment, the light receiving region is divided into the central portion 11a and the peripheral portions 11bL and 11bR. However, the light receiving region 11a may be further divided. For example, as shown in FIG. 19, the light receiving region 11 may be divided into a central portion 81aL, 81aR, an intermediate portion 81bL, 81bR, and a peripheral portion 81cL, 81cR. Although predetermined various processing methods such as shading correction of a captured image and flaw correction (correction of pixel values of the phase difference pixels 42a and 42b) may vary depending on the position of the light receiving region 11, the light receiving region 11 is changed as described above. In the case of fine division, it is preferable to divide the light receiving region 11 according to the division of various processing methods.

  In this case, as shown in FIG. 20, the opening area of the right phase difference pixel 42a may be enlarged stepwise in the order of the left central portion 81aL, the left intermediate portion 81bL, and the left peripheral portion 81cL. As described above, when the opening areas of the phase difference pixels 42a and 42b are enlarged in stages in accordance with different processing methods, the opening area is smoothly enlarged according to the distance from the center. (See FIG. 9) A good processing result can be easily obtained. That is, the stepwise expansion of the opening areas of the phase difference pixels 42a and 42b makes it easy to improve both the accuracy of the phase difference AF and the image quality of the captured image. In FIG. 20, the light receiving region 11 is divided into the central portions 81aL and 81aR, the intermediate portions 81bL and 81bR, and the peripheral portions 81cL and 81cR. However, as in the above-described embodiment, the light receiving region 11 is separated from the central portion 11a and the periphery. The same applies to the case of dividing into parts 11bL and 11bR. In the left phase difference pixel 42b, the opening area may be enlarged stepwise at the right central portion 81aR, intermediate portion 81bR, and peripheral portion 81cR as in the above embodiment.

  When the imaging lens 44 is a zoom lens, the principal ray angle 45 at each position changes depending on the zoom magnification, and thus the aperture areas of the phase difference pixels 42a and 42b at each position may not be uniquely determined. In this case, the phase difference pixel 42a at each position is set in accordance with the principal ray angle 45 in the telephoto end (when the focal length is the longest), the wide end (when the focal length is the shortest), or an intermediate between them. , 42b is preferably defined. However, when matched with the chief ray angle 45 at the telephoto end, the error at the wide end (deviation of specific sensitivity, etc.) is large. Conversely, when matched with the chief ray angle 45 at the wide end, the error at the telephoto end is large. Therefore, in order to achieve both the accuracy of the phase difference AF at the tele end and the wide end, the phase difference pixels 42a at the respective positions in accordance with the principal ray angle 45 in the middle between the tele end and the wide end. 42b is particularly preferable.

  In the above-described embodiment, the G pixel is the phase difference pixels 42a and 42b. However, as shown in FIG. 21, the R pixel and the B pixel may be phase difference pixels 42a and 42b. Of course, all of the phase difference pixels 42a and 42b may be formed of R pixels, and all of the phase difference pixels 42a and 42b may be formed of B pixels. Further, only two of R, G, and B may be provided with the phase difference pixels 42a and 42b.

  However, when the phase difference pixels 42a and 42b are provided for two or more colors of R, G, and B, the amount of decrease in sensitivity in the peripheral portion 11b is different for each color. Therefore, the opening areas of the phase difference pixels 42a and 42b are different for each color. It is preferable to change the enlargement ratio. For example, the enlargement ratio of the opening area of the phase difference pixels 42a and 42b of each color is set to B pixel> G pixel> R pixel, although it depends on the focal point of the micro lens 75 and the like. Of course, the enlargement ratio of the opening area is the same for the two colors, and only one color may be different (for example, B pixel = G pixel> R pixel). The reference for the enlargement ratio is the opening area of each color phase difference pixel 42a, 42b in the central portion 11a. In this way, if the enlargement ratio of the opening area of the phase difference pixels 42a and 42b is adjusted for each color, a signal having a good S / N can be obtained in the phase difference pixels 42a and 42b of each color. Easy to improve accuracy.

  In the above-described embodiment, the pixels of the solid-state imaging device 10 are arranged in a square, but the arrangement of the pixels is arbitrary. For example, the pixel arrangement may be a honeycomb arrangement as shown in FIGS. Further, the color arrangement of the color filter when the pixel arrangement is the honeycomb arrangement is arbitrary, but for example, the color arrangement shown in FIGS. 22 and 23 can be used. The color arrangement in FIG. 22 is an example in which columns of G pixels and columns in which two R pixels and two B pixels are alternately arranged are alternately arranged in a 45-degree oblique direction.

  In the above-described embodiment, when the pixels of the solid-state imaging device 10 are arranged in a square, the color filter 41 in units of 6 × 6 pixels is used. However, the arrangement of the color filters 41 is arbitrary. For example, when the pixels are arranged in a square array, as shown in FIG. 24, a so-called Bayer array in which 2 × 2 pixels surrounded by a broken line are arranged vertically and horizontally may be used.

  In the above-described embodiment and modification, in the 6 × 6 pixel unit of the color filter 41, the lower left G pixel of the upper right first subunit 41a and the lower left G pixel of the upper left second subunit 41b are phase-differenced. The example in which the pixels 42a and 42b are formed has been described, but the position of the G pixel that forms the phase difference pixels 42a and 42b is arbitrary. For example, the center G pixel of the upper right first subunit 41a and the center G pixel of the upper left second subunit 41b may be phase difference pixels 42a and 42b, respectively. Further, for example, the G pixel of the lower right second subunit 41b and the G pixel of the lower left first subunit 41a may be phase difference pixels 42a and 42b.

  Furthermore, in the above-described embodiment and modification, the paired two phase difference pixels 42a and 42b are provided in the same row, but the paired two phase difference pixels 42a and 42b are provided in different rows. May be.

  In the above-described embodiment, the three transistors Tr23, Ta24, and Ts25 form a pixel (see FIG. 1), but the pixel 21 (the normal pixel 43 and the phase difference pixels 42a and 42b) receives incident light respectively. The number of transistors and the like are arbitrary as long as photoelectric conversion can be performed and signals necessary for formation of a captured image and phase difference AF can be output. For example, the pixel 21 may be configured by providing a transistor for transfer between the PD 22 and the FD and using four transistors.

  In the embodiment and the modification described above, the light shielding layer 54 and the color filter 41 are stacked, but the color segments of the color filter 41 are formed so as to be embedded in the openings 55 and 56 of the light shielding layer 54. The light shielding layer 54 and the color filter 41 may be integrally formed.

  In the above-described embodiment and modification, the light shielding layer 54 and the color filter 41 are laminated in this order on the back surface of the p-type semiconductor substrate 53. However, the light shielding layer 54 and the color filter 41 may be laminated in the reverse order. good.

  In the embodiment and the modification described above, the openings 55 and 56 of the light shielding layer 54 are filled with a transparent material to flatten the light shielding layer 54. However, the openings 55 and 56 are filled with the material of the color filter 41. May be.

  In the embodiment and the modification described above, the solid-state imaging device 10 is a CMOS image sensor, but the solid-state imaging device 10 may be a CCD image sensor.

  In the above-described embodiment and modification, the solid-state imaging device 10 is a back-side illuminated image sensor, but the solid-state imaging device 10 may be a front-side illuminated (FSI) image sensor. The surface irradiation type image sensor is a type of image sensor in which light is incident on a PD via a wiring layer.

  In the above-described embodiment, in the light shielding layer 54, the light shielding material is also provided between the normal pixels 43, and the opening 55 of each normal pixel 43 is separated, but the light shielding material between the normal pixels 43 is not provided. All the openings 55 of the normal pixels 43 may be connected. In this case, the light shielding layer 54 is a layer in which a light shielding material is disposed only in a portion that restricts incident light in the phase difference pixels 42a and 42b.

  In the above-described embodiment, the primary color filter 41 is used, but a complementary color filter may be used. The color filter may include colorless (transparent) pixels, and the phase difference pixels 42a and 42b may be formed in these colorless pixels.

  In the above-described embodiment, the phase difference pixels 42a and 42b are formed asymmetrically in the left and right direction (lateral direction), and the left and right parallaxes are obtained by the phase difference pixels 42a and 42b. The direction in which information is obtained may be the vertical direction (vertical direction) or an oblique direction. In other words, the parallax in the vertical direction may be obtained by making the phase difference pixel structure (the position of the opening) asymmetric in the vertical direction and arranging the paired phase difference pixels vertically. In the case of obtaining oblique parallax, similarly, a pair of phase difference pixels having an asymmetric structure in the oblique direction may be arranged in the oblique direction.

  Further, in the above-described embodiment, only the phase difference pixels 42a and 42b that obtain the parallax in the horizontal direction are provided in the light receiving region 11, but the phase difference pixels 42a and 42b that obtain the parallax in the horizontal direction Two or more of the phase difference pixels to be obtained and the phase difference pixels to obtain the oblique parallax may be provided in the light receiving region 11. When providing a phase difference pixel that obtains vertical parallax and a phase difference pixel that obtains diagonal parallax, the phase difference pixels in each direction are also the same as the left and right phase difference pixels 42a and 42b of the above-described embodiment. It is preferable to enlarge according to the direction of the received light beam and the position in the light receiving region 11.

  In the above-described embodiment, some pixels in the light receiving region 11 are the phase difference pixels 42a and 42b. However, as shown in FIG. 25, all the pixels may be the phase difference pixels 42a and 42b. When all the pixels are phase difference pixels 42a and 42b, for example, a 3D image can be obtained with a single eye (one solid-state imaging device). FIG. 25 shows a case where the pixels are square array and the color filter 41 is used, but all pixels may be phase difference pixels 42a and 42b even when the pixels are honeycomb array and the color filters are Bayer array.

  In the above-described embodiment, a plurality of phase difference pixels 42a and 42b are provided uniformly in the light receiving region 11, but the phase difference pixels 42a and 42b may be at least in the central portion 11a and the peripheral portions 11bL and 11bR. The number, arrangement, and distribution of the phase difference pixels 42a and 42b are arbitrary.

  The solid-state imaging device 10 of the present invention is suitable for a camera unit mounted on a thin digital camera, a mobile phone, a PDA, a smart photon, or the like. In particular, it is suitable for a camera or a camera unit that is close to the imaging lens 44 and has a large principal ray angle in the peripheral portion.

DESCRIPTION OF SYMBOLS 10 Solid-state imaging device 11 Light reception area | region 11a Center part 11bL, 11bR Peripheral part 21 Pixel 42a, 42b Phase difference pixel 43 Normal pixel 55, 56L, 56R Aperture

Claims (10)

A plurality of normal pixels that are arranged in a light receiving region where an image of a subject is formed, and isotropically receive incident light;
A plurality of pixels provided in the light receiving region and having an opening eccentrically arranged in a first direction, and a first phase difference pixel that selectively receives light reaching the first direction side of the incident light. When,
A plurality of pixels provided in the light receiving region and having an opening that is eccentrically arranged in a second direction opposite to the first direction, and selectively transmits light incident on the second direction side of the incident light. A second phase difference pixel for receiving light,
The first phase difference pixel in the peripheral portion on the second direction side of the light receiving region is compared with the first phase difference pixel in the central portion of the light receiving region and the peripheral portion on the first direction side. The area of the first opening is large;
The second phase difference pixel in the peripheral portion on the first direction side of the light receiving region is different from the second phase difference pixel in the peripheral portion on the central portion and the second direction side. A solid-state imaging device having a large area of two openings. In the first phase difference pixel in the peripheral portion on the second direction side, the first opening is extended to the second direction side with respect to that of the central portion,
2. The solid according to claim 1, wherein, in the second phase difference pixel in the peripheral portion on the first direction side, the second opening is extended to the first direction side with respect to the central portion. Imaging device. In the first phase difference pixel in the peripheral portion on the second direction side, the center position of the first opening is on the second direction side with respect to the central portion,
The said 2nd phase difference pixel in the said peripheral part of the said 1st direction side WHEREIN: The center position of the said 2nd opening exists in the said 1st direction side rather than the thing of the said center part. Solid-state imaging device.   The first phase difference pixel in the peripheral portion on the second direction side and the second phase difference pixel in the peripheral portion on the first direction side are photodiodes for photoelectric conversion. The solid-state imaging device according to claim 1, which is smaller than that of the central portion.   The area of the first opening extends from the central part to the peripheral part on the second direction side, and the area of the second opening extends from the central part to the peripheral part on the first direction side. The solid-state imaging device according to any one of claims 1 to 4, wherein the solid-state imaging device is enlarged. The first phase difference pixel and the second phase difference pixel are provided in a plurality of colors,
The first opening of the first phase difference pixel in the peripheral portion on the second direction side; and
6. The enlargement ratio of the second opening of the second phase difference pixel in the peripheral portion on the first direction side is determined for each of the colors. 6. Solid-state imaging device. When an image of the subject is formed on the light receiving area by a zoom lens,
Depending on the incident angle of the incident light when the focal length of the zoom lens is the longest and shortest, the first phase difference pixel in the peripheral portion on the second direction side The area of each said 2nd opening of the said 2nd phase difference pixel in the peripheral part of the said 1st opening and the said 1st direction side is defined in any one of Claims 1-6. Solid-state imaging device. The first phase difference pixel in the peripheral portion on the first direction side has a smaller first opening than the first phase difference pixel in the central portion,
The said 2nd phase difference pixel in the said peripheral part of the said 2nd direction side has said 2nd opening small with respect to the said 2nd phase difference pixel in the said center part, The any one of Claims 1-7 The solid-state imaging device according to item. A microlens that collects the incident light is provided for each pixel,
9. The solid-state imaging device according to claim 1, wherein the microlenses in the peripheral portion are arranged eccentrically in the direction of the central portion according to an incident angle of the incident light to each pixel. . A plurality of pixels provided in a light receiving region where an image of a subject is formed and having an opening that is eccentrically arranged in a first direction, and selectively receives light that reaches the first direction of the incident light. A first phase difference pixel that
A plurality of pixels provided in the light receiving region and having an opening that is eccentrically arranged in a second direction opposite to the first direction, and selectively transmits light incident on the second direction side of the incident light. A second phase difference pixel for receiving light,
The first phase difference pixel in the peripheral portion on the second direction side of the light receiving region is compared with the first phase difference pixel in the central portion of the light receiving region and the peripheral portion on the first direction side. The area of the first opening is large;
The second phase difference pixel in the peripheral portion on the first direction side of the light receiving region is different from the second phase difference pixel in the peripheral portion on the central portion and the second direction side. The area of 2 openings is large,
A solid-state imaging device in which all pixels arranged in the light receiving region are either the first phase difference pixel or the second phase difference pixel.

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